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There is a need for a shift towards circular economy in the construction sector and design philosophies as Design for Deconstruction and Reuse (DfDR) and Design for Adaptability (DfA) are being developed as means to design out waste and enhance resource efficiency. However, applying these philosophies is not yet common practice. The amount of DfDR/A timber buildings described in literature is limited. This study aims at increasing and spreading knowledge on DfDR/A for timber buildings. It has four goals: 1) To suggest methods to apply DfDR/A. 2) To suggest new design solutions. 3) To collect experiences on connections in relation to DfDR. 4) To suggest how guidelines for deconstruction and reuse can be formulated. The study presents three methods that all proved valuable in applying DfDR/A: one discussion-based method to improve an already existing timber building design, one indicator system to assess the DfDR/A potential of building designs, and one matrix to guide design decisions. We used the first method to conduct five case studies in four European countries. The studied designs were judged to be well or relatively well adapted for deconstruction and reuse already today. The fact that the studied buildings are all offsite manufactured and of modular composition benefits the deconstruction process, partly because construction and deconstruction are similar processes so that the knowledge and infrastructure that companies have can be directly transferred to enable deconstruction and reuse. Where large modules can be recovered, the time and energy needed for deconstruction as well as the risk for damage will be reduced. Disadvantages to deconstruction and reuse identified were typically linked to the complexity of building modules and that individual components are not independent. This was reflected as irreversible or hidden connections, inaccessible services, interconnected layers of the structural modules and many different component sizes. One of the case study buildings, designed with mass timber panels, excelled in the simplicity and reduction of number of steps required for maximum material recovery. New designs suggested included making fasteners more accessible to deconstruction, avoiding letting sensitive materials as plastic foils and particle boards pass continuously over joints between elements, and (for cases where standard units are not already used) standardizing elements. One case suggested using solid wood components instead of engineered wood products to achieve durability. The study showed that simple changes in design can lead to an augmented reuse potential. Some of the new design solutions generated will be taken into production by the participating manufacturers. Insights on connections included recognizing the fact that the use of reversible screwed connections is not sufficient to ensure deconstructability and that although nailed or glued connections severely complicate reuse of components, they might be accepted within elements in case reuse on element level is the target. Guidelines for deconstruction and reuse were developed in all case studies. Taken as a group of studies, there are advantageous additions proposed to earlier guidance documents. Despite being based on the same source, the different plans suggested varied substantially. There was a noteworthy difference between manufacturers’ in-house plans to those proposed by architects, engineers, or researchers, which speaks to the uncertainty regarding the appropriate structure and format.

The circular economy is an efficient system to reuse materials reducing the amount of waste generated. In order to implement it in the timber sector, the InFutUReWood (Innovative Design for the Future Use and Reuse of Wood (Building) Components) is a European project studying the possibilities for reuse and recycling of timber from demolition for structural applications. Nowadays in Ireland and Spain, most of the wood waste is reduced to chips. In Ireland, chips are mainly used for energy production, pallet blocks, and composting, while in Spain are used for energy production and particleboard manufacture. Possible structural applications depend on the amount, dimensions, and condition of recovered timber. Most of the recovered timber in Ireland has medium size cross-sections, while in Spain it is mainly large cross-section. Cross laminated timber (CLT) is a good option for reuse and experimental tests are ongoing in Ireland on CLT manufactured from old timber trusses. However, for large cross-sections, direct reuse for rehabilitation works will be a more efficient use of the material. ProjectInFutUReWood is funded in Spain by the Ministerio de Ciencia, Innovación y Universidades (MICIU). Project reference PCI2019-103544. Diseño innovador para el futuro – uso y reutilización de componentes de edificación de madera. Project InFutUReWood is funded in Ireland by the Department of Agriculture, Food and the Marine under the DAFM research funding program. Project reference 18CENForestValue1. Project InFutUReWood is supported under the umbrella of ERA-NET Cofund Forest Value by Vinnova – Sweden´s Innovation Agency, Formas– Swedish Research Council for Sustainable Development, Swedish Energy Agency, the Forestry Commissioners for the UK, the Department of Agriculture, Food and the Marine for Ireland, the Ministry of the Environment for Finland, the Federal Ministry of Food and Agriculture through the Agency for Renewable Resources for Germany, the Ministry of Science, Innovation and Universities for Spain, the Ministry of Education, Science and Sport for Slovenia. Forest Value has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N° 773324. The authors would like to thank Mr. Paul Hogan from Hegarty Demolition (InFutUReWood Irish industrial partner), and demolition and waste management companies from Ireland and Spain for kindly supplying information. non-peer-reviewed

The Innovative Design for the Future Use and Reuse of Wooden building components (InFutUReWood) project aims to examine if recovered timber is suited for contemporary timber architecture. To address this aim, a study was undertaken as part of Work Package 3 to identify the current range of timber products obtained from demolition and their current and potential reuse. The study was conducted across all partner countries using a combination of site visits and industry surveys The information compiled shows that the motivation for deconstruction in each country depends mainly on the building location and site value. The type of timber available for recovery was largely contingent on the age of the structures. Building deterioration and rising building standards were common causes for demolition; however, a more significant incentive for urban demolition was market depreciation. In these instances, site clearance makes way for redevelopment, facilitating alternative building use or general urban renewal. An overview of international and national classification systems for timber waste from construction and demolition is presented. Differences were found between partner countries in terms of the potential to reuse recovered timber in loading bearing applications in buildings. Most timber extracted from construction and demolition across the surveyed counties is reduced to woodchip, regardless the size or quality of the extracted material. The main uses of the wood chip are particle board manufacture or bioenergy generation. Exceptions to this are mass timber, such as glulam, and old, large section timber members with high cultural value, which are reused directly. Potential alternative building products recovered timber are presented that will extend the lifespan of the material. non-peer-reviewed